More than 1,000 pages of newly released documents relating to the investigation into the Sandy Hook massacre revealed the gunman was obsessed with violence and mass murder, and held a "scorn for humanity" several years before he committed the school shooting.

The documents, obtained by the Hartford Courant from the Connecticut State Police following a five-year court battle, feature hundreds of pages of writing from Adam Lanza which help portray the state of his mind in the years before he killed 26 people, including 20 children, at the elementary school in Newtown on December 14, 2012.

Among the documents seized as part of the investigation is a book he wrote back in fifth grade with another boy which contains several pages of violent and graphic imagery and description.

According to the Hartford Courant, one chapter in Lanza's "Big Book Of Granny" includes a character named Dora the Beserker entering a day care center with Granny and her son in order to "hurt children."

In seventh grade, while he was attending St. Rose of Lima School, Lanza wrote an essay titled "Battles, destruction and war" that was so disturbing his teacher believed it proved he was "deeply troubled by feelings of rage, hate and (at least unconscious) murderous impulses," according to the state Office of Child Advocate report.

The teacher added that Lanza's writing was also "so graphic that it could not be shared."

Elsewhere, Lanza was found to have kept a highly detailed spreadsheet listing mass killings around the world dating back to 1786, which authorities believe he used to plan his own attack.

"He's not doing this for a term paper, this took a lot of work and a lot of effort, and so what are other possible reasons he could be doing this?" former FBI profiler Mary Ellen O'Toole told the Hartford Courant.

In other writings, Lanza described his hatred of fat people and gives a list of reasons why he wanted to remain underweight, including how "starving is an example of will power." He also believed doctors who examined him as a child had raped him, and wrote a screenplay which detailed a relationship between a 10-year-old boy and a 30-year-old man.

In one document, believed to be online communication with a fellow gamer, Lanza described his hatred of other people while also appearing to yearn for companionship.

"I incessantly have nothing other than scorn for humanity," he said. "I have been desperate to feel anything positive for someone for my entire life."

In an editorial note, the newspaper explained why they chose to highlight documents showing the disturbed mind of a man who murdered 26 people.

"Understanding what a mass killer was thinking not only paints a clearer picture of the individual, it helps us identify and understand red flags that could be part of a prevention formula for future mass shootings," the editorial said.

This handout crime scene evidence photo provided by the Connecticut State Police shows the Newtown Technology Team ID of Adam Lanza in the bathroom at the suspect's house on Yogananda St. following the December 14, 2012 shooting rampage at Sandy Hook Elementary School.Connecticut State Police via Getty Images